Measurement of Temperature and Relative Humidity with Polymer Optical Fiber Sensors Based on the Induced Stress-Optic Effect

Sensors

Arnaldo Leal-Junior¹  Anselmo Frizera-Neto¹  Maria José Pontes¹  Carlos Marques² 

[1] Graduate Program of Electrical Engineering of Federal University of Espirito Santo, 29075-910 Vitória, Brazil;Instituto de Telecomunicações, Campos Universitário de Santiago, 3810-193 Aveiro, Portugal;

关键词: polymer optical fiber;    temperature sensor;    relative humidity sensor;    stress-optic effect;   

DOI  :  10.3390/s18030916

来源: DOAJ

【 摘 要 】

This paper presents a system capable of measuring temperature and relative humidity with polymer optical fiber (POF) sensors. The sensors are based on variations of the Young’s and shear moduli of the POF with variations in temperature and relative humidity. The system comprises two POFs, each with a predefined torsion stress that resulted in a variation in the fiber refractive index due to the stress-optic effect. Because there is a correlation between stress and material properties, the variation in temperature and humidity causes a variation in the fiber’s stress, which leads to variations in the fiber refractive index. Only two photodiodes comprise the sensor interrogation, resulting in a simple and low-cost system capable of measuring humidity in the range of 5–97% and temperature in the range of 21–46 °C. The root mean squared errors (RMSEs) between the proposed sensors and the reference were 1.12 °C and 1.36% for the measurements of temperature and relative humidity, respectively. In addition, fiber etching resulted in a sensor with a 2 s response time for a relative humidity variation of 10%, which is one of the lowest recorded response times for intrinsic POF humidity sensors.

【 授权许可】

Unknown